speaking of grounding that is one thing Im glad I dont have an M for. 10 year old boat probably grounded 1 or 2 hundred times and still on the original swing keel.
Glad I'm not the only one that does that! I've got a swing keel attitude with a daggerboard boat!
The “Achilles Heel” of the Centerboard trailer sailboat. The long hull cavity for the swing centerboard creates Drag Turbulence while sailing and motoring. Requires a diligent maintenance program to avoid issues, leaving the board stuck down. The pivot hole also wears among other shortfalls.
I was able to address all your concerns/observations with my centerboard mod. I removed the pull line. The board never completely leaves the trunk so whatever turbulance there is must be less than before, maybe. It works like a charm, both mechanically and sailing performance wise. Just don't forget to unlock the board when going on the trailer.
Gerald Gordon
I wanted to include your most interesting upgrade/modification, but truthfully, it is so slick I could not grasp how you deploy and retrieve this board modification. We need understanding how this Mod addresses the Centerboard "Achilles Heel"
Maybe you could detail the operation with some real photos or simulated diagrams.
Were really interested from your post in the Mods section.
I'm sure some people would agree that the hull shape on the X-boats does not offer a surface to resist the side ward slipping motion when the is sailing. This slipping can also be observed when sailing at anchor. What's needed is a surface....
The three pictures I posted in the mod section show the mechanical concept.
As one can see from the other pictures of the mod, I installed a pipe next to the compression post. That pipe is a sleeve. The pipe that is connected to the CB rides in the sleeve. The CB pipe is lifted and lowered by using the handle. The wood strip with the round holes allows for depth adjustment.
I removed the line from the system and I adjust depth via the wood/hole gauge.
To remove the CB the boat needs to be in the water...not too deep. Remove the handle by unscrewing one of the black plastic handle knobs and pull out the shaft. The board slides out of the trunk and can be take to shore for whatever reason/repair.
There is no more swing hole. The CB is suspended from the CB pipe (seen in the three mod pictures) I have glassed a 1/2" SS rod into the CB which runs through the CB pipe. There is no more pivot hole.
I can lower the CB 11" max. About 3-4" always stay in the trunk so there is always something in the cavity. For motoring, I'll lower 3" and for sailing depends on conditions.
The CB does not pivot down. It is more like and upside down toaster. The bread pops out nice and toastie....
Seems to be a change from a high aspect foil to a low aspect foil.
In theory..
Highest lift to drag ratio is a high aspect vertical foil (ie, M) but this foil also stalls at the lowest angle of attack. (in the windsurfing world, the most efficient racing "formula boards" have high aspect vertical foils. Since the boards go fast, the fins typically generate all the lift they need at low angles of attack). When going slow, the necessary angle of attack to generate the required lift can be too high and cause the fin to stall.
The same foil swept back will require a higher angle of attack to generate the same lift as the vertical foil and will generate more drag (induced drag which is a result of the foil genererating lift) in doing so - ie, they have a lower L/D. However, the swept back foil can be taken to higher angles of attack before stalling (in the windsurfing world, wave boards which must tolerate tight radius turns have very swept back fins - and they are not anywhere near as fast as the high aspect vertical foils).
Low aspect foil - worst Lift to drag. Requires a lot of angle of attack to generate the same lift and has the most induced drag - however, it would be very resistant to stall and could be operated at highest angles of attack. Probably best when going very slow but wont be as fast as a high aspect vertical foils as soon as the boat has any speed.
Hello Walt,
That's all interesting information. I'm sorry to say I'm not an engineer nor do I have the tools to redesign the X-boat. If I were, and had the tools, one of the first things I would have done is to put the companion way off to the side and made the head larger. Be that as it may.
I have by no means pushed the X-boat to its sailing limits. Some on this board may have. From where I'm sitting the boat is compromised in the hull. What to do? Both the M and X seem to be manifestations of this compromise. Centerboard vs. Dagger board. I think that my mod could qualify as a keel board in that is offers more resistance (a la a keel) but can also by stowed like a CB or Dagger.
I suppose that the high/low ratio aspects you are referring to would be very important in certain circumstances such as racing. But the X-boat is by no means a race boat and, as delivered from the factory, a crappy sailboat. It is however, a roomy, and when fixed up, nice comfortable place to hang and observe life.
My mod is an attempt to improve on the boat's sailing characteristics. For a while there was much discussion about weighty centerboards. Kudos to all the pioneers that went down that road. From what they observed the main result of that mod is that the boat does not heel as quickly as normal.
I think the heeling of the boat is one of its biggest charms. It gets the adrenaline going. But to be able to steer a bit closer to the wind...that's monster. It would be nice if I could come up with some objective tests to show if in fact there is any sailing improvement. I think there is...plenty. But of course, how can any parents be critical of their kids?
My 13 yo son went to sailing school and they told him boats are faster when not heeled so much. However, I love to sail with the boat (26S) heeled as much as possible and it seems many others here do also. But I have to constantly listen to my son scold me..
Your mod is interesting and hopefully my post wasnt passing judment at all, just something which might be interesting. I think the mod will do some things well, other worse. As you pointed out, everything is usually a trade off and no one implementation does everything the best. You have to pick whats important to you and what you have could be very good in light winds and of course you can do full on sailing in some really shallow water. Stalling is probably almost impossible. But once the M configuration gets going, it will probably be faster.
FYI - in the original question, I would vote for an M with a swing centerboard. Ive smacked my "S" centerboard a few times already and only had the boat one season. The leading edge of the centerboard has a bunch of BIG dings/indents in it from the previous 17 years of ownership..
I agree with your son's teacher. My rule of thumb has always been that yachts & sailboats run best at around 8-10° of heel.. any more than that and you're just spilling the wind out the top.
and can be quite different but above about 15 degrees of heel, the leeway goes up dramatically to the point where close hauled you will almost go sideways...I never let her go over 15 if Im trying to get somewhere..
You didn't point out the post that discussed the reason for the rudder rebuild. I left the rudders down as I pulled the boat up the ramp at Stockton and ground off the bottom 1/2 inch. It had nothing to do with grounding!!
BTW I wasn't arguing against Daggers merely defending swing keels.
Catigale wrote: and can be quite different but above about 15 degrees of heel, the leeway goes up dramatically to the point where close hauled you will almost go sideways...I never let her go over 15 if Im trying to get somewhere..
30 degrees is more fun..
I thought the reason Roger suggests 15 degrees heel is that any greater angle of heel gradually defeats the lift of the CB foil ... it becomes ineffective. Since most of us always sail at 15+ degrees anyway, that might be a good endorsement of Gerald's low-aspect board. Probably means any standard Mac can scoot right by GG in lighter winds, with better lift ... but maybe at 30 degrees, his board has less leeway??
The comments in this thread regarding the centerboard well of the 26X raised a question for me: Having never seen a 26X upside down, I always just assumed they had a centerboard well "gasket" like other small centerboard boats I have sailed.
In college I raced 420's and 470's, and a few larger boats, and the "gasket" was two long strips of relatively stiff-but-flexible plastic mounted on either side of the centerboard well, such that when the centerboard was fully retracted the gasket strips slightly overlapped each other, presenting a relatively smooth surface instead of a big hole/gap. When the board was lowered, it would slip between the edges which would flex around and essentially mold themselves to the board, again keeping a smoother surface. Note: the gasket in no way or form kept water out, it simply reduced turbulence. When you went out and your 420 was suddenly slower than everyone else's - the gasket was one of the first things to check - it made a huge difference.
I believe some other centerboard boats have something more like a stiff-bristle brush strip up either side of the well - even though the brush is not glossy smooth it is still "faster" than a wide open hole.
I take it from the comments here that the X does not have any such gasket installed?
and
can be quite different but above about 15 degrees of heel, the
